Day 26.1.txt

121. Best Time to Buy and Sell Stock

You are given an array prices where prices[i] is the price of a given stock on the ith day.

You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock.

Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.

 

Example 1:

Input: prices = [7,1,5,3,6,4]
Output: 5
Explanation: Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5.
Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.
Example 2:

Input: prices = [7,6,4,3,1]
Output: 0
Explanation: In this case, no transactions are done and the max profit = 0.
 

Constraints:

1 <= prices.length <= 105
0 <= prices[i] <= 104


class Solution {
    public int maxProfit(int[] p) {
        int i,j=p[0],k=p[0],j1=j,k1=k;
        for(i=1;i<p.length;i++)
        {
            if(j>p[i])
            {
                j=p[i];
                k=p[i];
            }
            else if(p[i]>k)
            {
                k=p[i];
            }
            if((k-j)>(k1-j1))
            {
                k1=k;
                j1=j;
            }
        }
        return k1-j1;
    }
}